CZ292297B6 - Unitary disposable absorbent article - Google Patents

Abstract

In the present invention there is disclosed a unitary disposable absorbent article comprising a chassis assembly (22) having lateral edges (60) and leg edges (61). Said chassis assembly (22) comprises a topsheet (24) and a backsheet (26) and an absorbent core (28) positioned within the topsheet (24) and the backsheet (26). The absorbent core (28) has side edges (58) and waist edges (59). It further comprises an extensible waist belt (32) attached to the chassis assembly (22) next to one of the lateral edges (60) and a closure system (34) closure system joined to said extensible waist belt (32) for fastening said absorbent article on a wearer. The absorbent article (20) has its absorbent surface. The extensible waist belt (32) has a central waist panel (56) and a pair of side panels (57), one being disposed on each side of the central waist panel (56). The side panels (57) extend laterally outwardly from the central waist panel (56) beyond the leg edges (61) of the chassis assembly (22). The extensible waist belt (32) comprises a structural elastic-like film web (52). Said structural elastic-like film web (52) comprises a strainable network including a first region (64) and a second region (66) having both substantially equal material composition. The first region (64) exhibits a first resistive force during axial elastic elongation and the second region (66) a second different resistive force during further axial elongation to thereby generating, at use, at least two stages of the resistive forces. The invented disposable absorbent article is designed to fit an infant having a maximum rise dimension defined as a distance from the infant's navel through the crotch area to the small of the back and being less than 443 mm and a fit index of absorbent article area to the above rise dimension of less than or equal to 240.

Description

Unit disposable absorbent article

Technical field

The present invention relates to a unitary disposable absorbent article, generally absorbent systems that enhance the wearer ' s comfort and health of the skin by substantially reducing the coverage and closing of the wearer ' s skin by the absorbent system.

BACKGROUND OF THE INVENTION

Young children and other incontinent individuals wear absorbent systems, such as disposable absorbent articles, to receive and contain urine of body exudates. Disposable absorbent articles act both by retaining excreted exudates and by isolating these materials from the wearer ' s body, underwear and bedding.

Although the previously known disposable absorbent articles do in fact perform their intended function, any traditional design suffers from one or another deficiency in the ability to absorb body fluids, protect the wearer's underwear from contamination, wearer comfort, and healthy skin condition.

A typical disposable absorbent article comprises an absorbent member positioned between a liquid permeable body contacting element and a liquid impermeable barrier. This absorbent element (sometimes called the absorbent core) is intended to receive and retain urine and other body exudates. The body contacting element (sometimes referred to as the topsheet) is intended to provide comfortable contact with the surfaces of the wearer's body while allowing free passage of fluids through itself into the absorbent element. The protective barrier (sometimes referred to as the backsheet) is intended to prevent urine and other body exudates from penetrating the disposable absorbent article and soiling the wearer's undergarments.

Although the protective barrier or backsheet is highly effective in preventing penetration and thus helps to retain liquid within the disposable absorbent article, the barrier closes the wearer's skin and makes the disposable absorbent article uncomfortable to wear, which can lead to some problems with healthy skin condition. To further aggravate this problem, the disposable absorbent articles of the prior art are relatively large in relation to the size of the wearer to be fit. Such designs were considered desirable because consumers preferred larger disposable absorbent articles because of their limited tendency to leak. Although larger, disposable absorbent articles may have a reduced tendency to leak and thus protect underwear and bedding from soiling. These products also have a negative impact on the wearer ' s comfort and health by covering and enclosing a larger area of the skin. Closing the wearer ' s skin with a protective barrier or backsheet captures urine and other body exudates of the wearer's skin. Moisture trapped in the skin causes it to hydrate, threatening skin health. Excessive skin hydration can lead to skin irritation, rashes and other related skin problems.

WO-A-90/04377 discloses a diaper that is configured to fit better and be more comfortable by providing the diaper with a relatively thin, narrow absorbent panel.

WO-A-91/08 725 discloses a web that is used with a disposable diaper.

GB-A-2 244 422 discloses a diaper with a belt having a fastener for improving the fit of the diaper around the wearer.

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Thus, it is an object of the invention to provide a disposable absorbent article that provides enhanced wearer comfort.

It is another object of the present invention to provide a disposable absorbent article that provides the wearer with improved skin health.

It is another object of the present invention to provide a disposable absorbent article that substantially reduces the size of the wearer ' s skin area that is covered and closed by the disposable diaper.

These and other objects of the present invention will become more apparent when considered with reference to the following description and taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides unitary, disposable absorbent articles, such as disposable diapers and the like, having a unique design that improves wearer comfort and skin health. The absorbent articles include an outer shell, preferably comprising a liquid pervious topsheet and a liquid impermeable backsheet, an absorbent core disposed within the outer shell, and a closure system coupled to the outer shell to secure the absorbent article to the wearer. The absorbent core has an absorbent core area and the absorbent article has an absorbent article area.

The present invention also provides unitary disposable absorbent portions of undergarments, such as sports panties, that have a unique design to improve wearer comfort and skin health. Such absorbent garments have a pair of leg openings and a belt opening. The absorbent articles include an outer shell and an absorbent core disposed within the outer shell. The absorbent core has its absorbent core area and the absorbent garment has its absorbent garment area.

The absorbent articles of the present invention preferably have a relatively low fit index. This index of fit of the absorbent article directly corresponds to the comfort and health of the wearer's skin. The "fit index" as used herein refers to the relationship of the size of a certain absorbent article to the size of a particular wearer. The fit index is determined by dividing the area of the absorbent article by a characteristic dimension for the growth of the largest wearer, calculated to fit the absorbent article. The largest wearer dimension of an absorbent article refers to the characteristic dimension Y of the largest wearer, or the maximum characteristic dimension to be expected to fit the absorbent article, the absorbent article being designed to fit a small child having the characteristic a dimension to increase from about X, which is a characteristic dimension to increase in the smallest wearer expected to fit the diaper, up to about Y.

A lower fit index is preferred because less wearer ' s skin is covered and closed by a certain absorbent article, thereby enhancing the comfort and health of the wearer's skin. Conversely, a higher fit index is less preferred because more absorbent article is covered and closed by a particular wearer, making the absorbent article less comfortable to wear as it exposes the wearer's skin to potentially unhealthy conditions.

The absorbent articles of the present invention preferably have an fit index of less than or equal to about 240, more preferably less than or equal to about 238, and most preferably less than or equal to about 236.

The absorbent articles of the present invention also preferably have a relatively low absorbency index. The " ability index " as used herein refers to the relationship of the size of the absorbent core to the size of the wearer. The absorption index is determined by dividing the absorption area

The core of the core has a characteristic Y dimension for the growth of the largest wearer expected to fit the absorbent article. A lower absorbency index is more preferred because the use of less material on the absorbent core makes the absorbent article more comfortable to wear. Conversely, a higher absorbency index is less preferred because more absorbent material makes the absorbent article less comfortable to wear.

The absorbent articles of the present invention preferably have an absorbency index of less than or equal to about 95, more preferably less than or equal to about 90, and most preferably less than or equal to about 85.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the description is terminated by the claims specifically indicating and clearly defining the subject matter considered to be the present invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which:

Giant. 1 is a plan view of an embodiment of the disposable diaper of the present invention in partial cross-section to more clearly illustrate its backing structure, with the diaper inner surface facing the viewer.

Giant. 2 is a cross-sectional view of the disposable diaper shown in FIG. 1 taken along line 2-2 of FIG. 1.

Giant. 3 is a plan view of an alternative embodiment of a diaper of the present invention.

Giant. 4 is a plan view of another alternative embodiment of a diaper of the present invention.

Giant. 5 is a plan view of a particularly preferred embodiment of a structural elastic-like film (abbreviated SELF) having an extensible mesh according to the present invention, with deformations facing the viewer.

Giant. 5A is a perspective view of a segment of a web of the structural, resilient film of FIG. 5 in an unstretched state.

Giant. 5B is a spatial illustration of a segment of the web of the flexible film of FIG. 5 in a stressed state corresponding to phase I on the force-elongation curve shown in FIG. 6.

Giant. 5C is a spatial representation of a segment of the web of the flexible film of FIG. 5 in a stressed state corresponding to the phase Π on the force-elongation curve shown in FIG. 6.

Giant. 6 is a graph of the resistive force versus percent elongation, comparative behavior of a web of a structural, resilient film of the present invention as shown in FIG. 5, with an otherwise identical, flat web of the same polymeric base material.

Giant. 7 is a graph of the elastic hysteresis behavior of the structural as resilient film of FIG. 6 when the web is subjected to a 60% elongation and its hysteresis reaction is examined.

Giant. 8 is a simplified side view of a particularly preferred apparatus used to form this portion of a web of a structural, like, flexible film in accordance with the present invention.

Giant. 9 is a plan view of opposing interlocking plates of the device of FIG. 8 laid side-by-side, showing their interlocking surfaces.

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Giant. 10 is a simplified side view of a static press used to form at least a portion of a base film into a web of a structural as well as flexible film in accordance with the present invention.

Giant. 11 is a simplified side elevational view of a continuous dynamic press used to form predetermined portions of a base film into a web of a structural as resilient film according to the present invention.

Giant. 12 is a simplified pictorial illustration of an apparatus used to form at least a portion of a base film into a web of a structural, resilient film of the present invention.

Giant. 13 is a simplified pictorial illustration of yet another apparatus used to form at least a portion of a base film into a web of a structural, resilient film of the present invention.

Giant. 14 is a graph of the resistive force versus percent elongation comparing the behavior of an alternative web of structurally resilient film that is a laminate comprised of a polymer film layer and a non-woven adhesive bonded layer having an extendable web of the invention with an otherwise identical, unformed planar with a basic sheet material.

Giant. 15 is a graph of the elastic hysteresis behavior of a web material having the elongate mesh of FIG. 14 when the web is subjected to a 60% elongation and its elastic hysteresis reaction is examined.

Giant. 16 is a perspective view of an embodiment of a sports pant according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "absorbent article" means articles that absorb and contain body exudates, and more particularly it relates to articles that are placed against or near the body of the wearer to absorb and retain the various exudates excreted by the body. The term "disposable" is used herein to mean absorbent articles that are not intended to be recovered or otherwise reused or to be reused as an absorbent article (ie, intended to be discarded after a single use and preferably recycled, composted or otherwise disposed of in a manner compatible with the protection of the environment). The term "unitary" absorbent article means absorbent articles that are formed from separate parts joined together to form an ordered unit (s) so as not to require separate handling portions, such as a separate holder or pad, a separate belt and pad, or panties and pad. A particularly preferred embodiment of the absorbent article of the present invention is the unitary disposable absorbent article, diaper 20 shown in Figure 1. As used herein, the term "diaper" means an absorbent article that is generally worn by infants or incontinent persons around the lower torso. . However, it should be understood that the present invention is also applicable to other absorbent articles such as incontinence pants, sports pants, feminine hygiene garments and the like.

Giant. 1 is a plan view of the diaper 20 of the present invention in an uncontracted, flattened state (i.e., its normally resilient contraction is stretched), with its structures cut away to more clearly illustrate the diaper structure 20, showing that portion of the diaper 20; which is in contact with the wearer, or its inner surface. As shown in Fig. 1, the diaper 20 is generally "T-shaped" and comprises: (a) a chassis assembly 22, preferably comprising: an outer shell, an absorbent core 28 disposed within the outer shell, and a flexible leg cuff 30 around the legs (b) an extensible waistband 32 and (c) a fastening system for fastening the diaper to the wearer comprising a pair of strap tabs 34. The outer wrapper preferably comprises a liquid pervious topsheet 24 and a liquid impervious backsheet 26 joined to the topsheet 24. .

-4GB 292297 B6

The diaper 20 shown in Figure 1 has an inner surface 36 (facing the viewer in Figure 1), an outer surface 38 on the side opposite the inner surface 36. the first waist region 40, the second waist region 42, on the side opposite the first waist region. region 40 and circumference defined by the outer edges of the diaper 20, wherein the longitudinal edges are labeled 44 and the end edges are labeled 46. (Although one skilled in the art will recognize that the diaper is usually described as having a pair of waist regions and crotch region between these waist regions) , in this application, for the sake of simplicity, the diaper 20 is described as having only waist regions, each waist region comprising a portion of a diaper, which would typically be designated as a crotch region). The inner surface 36 of the diaper 20 includes that portion of the diaper 20 that is disposed adjacent the body of the wearer during use (i.e., the inner surface 36 is generally at least a portion of the topsheet 24 and other portions attached to the topsheet 24). The outer surface 38 comprises that portion of the diaper 20 that is positioned away from the body of the wearer (ie, the outer surface 38 is generally comprised of at least a portion of the backsheet 26 and other portions attached to the backsheet 26). The first waist region 40 and the second waist region 42 extend, respectively, from the peripheral end edges 46 to the lateral centerline 48 of the diaper 20. (The lateral direction (direction or width x) is defined as a direction parallel to the lateral centerline 48 of the diaper 20; the longitudinal direction (direction or length y) is defined as the direction parallel to the respective longitudinal axis 49 and the axial direction (direction or thickness Z) is defined as the direction passing through the thickness of the diaper 20).

Giant. 1 shows a particularly preferred embodiment of a chassis assembly 22 in which the topsheet 24 and backsheet 26 have overall length and width dimensions greater than the same dimensions for the absorbent core 28. The topsheet 24 and backsheet 26 extend beyond the edges of the absorbent core 28, thereby they form portions of the edge of the diaper 20. This edge defines a respective outer periphery, or in other words, respective edges of the diaper 20. This edge includes longitudinal edges 44 and end edges 46.

Giant. 2 is a cross-sectional view of the diaper 20 taken along the section line 2-2 of FIG. 1. FIG. 2 illustrates the assembly of the chassis assembly 22, the belt 32, and the connection of the belt 32 to the chassis assembly 22. The chassis assembly 22 includes an upper layer 24, a backsheet 26, and an absorbent core 28 (generally shown in FIG. 2). The topsheet 24 and backsheet 26 preferably extend longitudinally outwardly beyond the waist edge 59 of the absorbent core 28 so as to form an end flap 62; at the distal edge 63 of the end flap 62, a lateral edge 60 of the chassis assembly 22 is formed by the edge of the topsheet 24 and the backsheet 26. The waistband 32 is attached to the end flap 62 of the chassis assembly 22 at the lateral edge 60. As shown in FIG. 32 is preferably directly attached to the backsheet 26 by the belt attachment element 50. The belt 32 is shown in Fig. 2 as comprising a web of a structural, resilient film 52 (as further described herein), preferably comprised of a laminate of two or more layers, in the embodiment shown in Fig. 2, comprising three layers: an inner layer 53, an outer layer 55 and a plan layer 54 disposed between the inner layer 53 and the outer layer 55. The inner layer 53 is a layer to the backsheet 26 by the belt attachment element 50.

The assembly of diaper chassis 22 is shown in Figure 1 as comprising the diaper main body (chassis). The assembly of chassis 22 comprises at least an absorbent core 28, preferably an outer shell layer comprising respective topsheet 24 and backsheet 26, as advantageously of elastic cuffs 30 around the legs. The chassis assembly 22 has a pair of leg edges 61 that typically form part of the longitudinal edges 44 of the diaper and a pair of lateral edges 60. In the embodiment shown in Fig. 1, the extensible waistband 32 is attached to one of the lateral edges while the other lateral edge forms one of the end edges Thus, the chassis assembly 22 includes a diaper main structure with other modifications added to form the composite diaper structure. An exemplary chassis of the present invention is that described in U.S. Patent 3,860,003.

The absorbent core 28 may be any absorbent means capable of absorbing and retaining liquids such as urine and certain body exudates. The absorbent core 28 has a garment facing surface, a body facing surface, side edges 58, and waist edges 59. The absorbent core 28 can be manufactured in a wide variety of sizes and shapes (eg, rectangular, hourglass, T-shaped) , asymmetric, etc.) and a wide variety of liquid-absorbing materials commonly used in disposable diapers and other absorbent articles such as

For example, pulverized wood pulp, commonly referred to as airfelt. Examples of other suitable absorbent materials include creped cellulose wadding, meltblown polymers including coform, cross-linked cellulose fibers, tissue paper comprising tissue paper webs and tissue paper laminates, absorbent foams, absorbent sponges, superabsorbent polymers, absorbent gelling materials, or any other equivalent material or combination of materials. Also, the arrangement and construction of the absorbent core may be varied (for example, the absorbent core may have zones of varying overall thickness, hydrophilic gradient, superabsorbent gradient, or absorption zones of lower average density and lower basis weight, or may include one or more layers or structures) . However, the total absorbent capacity of the absorbent core 28 should be compatible with the intended loading and intended use of the diaper 20. Furthermore, the respective size and absorbent capacity of the absorbent core 28 may vary to accommodate wearers ranging from infants to adults. . A particularly preferred embodiment of the diaper 20 has a rectangular shaped absorbent core.

The absorbent structure useful as the absorbent core 28 of the present invention, which has achieved widespread acceptance and commercial success, is described in U.S. Patent Nos. 6,610,678, 4,673,402, 4,888,231 and 4,834,735. The absorbent core 28 is preferably an absorbent core 28. the dual layer structure described in US 5,234,423.

The backsheet 26 is positioned adjacent the garment facing surface of the absorbent core 28 and is preferably attached thereto by such fastening means (not shown) well known in the art. For example, the backsheet 26 may be secured to the absorbent core 28 by a uniform, continuous layer of adhesive, a patterned layer of adhesive, or by providing separate lines, spirals, or points of adhesive. Adhesives found to be compliant are manufactured by the H.B.Fuller Company of St. Petersburg. St. Paul, Minnesota, USA, and on the market are available as HL-1,258. The attachment means will preferably comprise an open pattern web of adhesive fibers as described in U.S. Patent 4,573,986. a plurality of lines of adhesive fibers twisted into a spiral pattern as shown in the apparatus and methods shown in U.S. Patent 3,911,173, U.S. Patent 4,785,996, and U.S. Patent 4,842,666. Alternatively, the attachment means may include thermal bonds, pressure bonds, ultrasonic joints, dynamic mechanical joints, or any other attachment means or combinations of those attachment means known in the art.

The backsheet 26 is liquid impermeable (e.g., urine) and is preferably made of a thin plastic film, although other flexible liquid impervious materials may also be used. As used herein, the term "flexible" refers to those materials that are compliant and easily conform to the overall shape and contours of the human body. The backsheet 26 prevents the exudates absorbed and retained in the absorbent core 28 from wetting articles that are in contact with the diaper 20, such as sheets and undergarments. The backsheet 26 may thus comprise a woven or nonwoven material, a polymeric film, such as a thermoplastic film of polyethylene or polypropylene, or a composite material, such as a film-coated nonwoven material. Preferably, the backsheet is a thermoplastic film having a thickness of from about 0.012 mm to about 0.051 mm.

The backsheet 26 may allow vapors to escape from the absorbent core while still preventing exudates from passing through the backsheet 26.

The topsheet 24 is disposed on that surface of the absorbent core 28 that is adjacent the body surface and is preferably attached thereto and to the backsheet 26 by attachment means (not shown) such as those well known in the art. Suitable attachment means are described with respect to the attachment of the backsheet 26 to the absorbent core 28. As used herein, the term "bonded" includes those arrangements by which an element is directly attached to the other element by attaching the element directly to the other. and the arrangements by which the element is indirectly attached to the second element by its connection

-6GB 292297 B6 to the intermediate element (or elements), which in turn is connected to the second element. In a particularly preferred embodiment of the present invention, the topsheet 24 and the backsheet 26 are directly connected to each other along the periphery of the diaper and are indirectly joined together by their direct connection to the absorbent core 28 by means of an appropriate attachment means (not shown).

The topsheet 24 is flexible, soft to the touch and non-irritating to the wearer's skin. Furthermore, the topsheet 24 is permeable to liquids (e.g., urine) to allow it to readily penetrate through its thickness. A suitable topsheet 24 may be manufactured from a wide variety of materials such as porous foams, reticulated foams, apertured plastic foils, or woven or nonwoven strips of natural fibers (e.g., wood or cotton fibers), synthetic fibers (such as polyester or polypropylene fibers). ) or a combination of natural and synthetic fibers. Preferably, the topsheet 24 is made of a hydrophobic material to isolate the wearer's skin from liquids that have passed through the topsheet 24 and are contained within the absorbent core 28 (i.e., prevent rewetting). When the topsheet 24 is made of a hydrophobic material, at least its topsheet is treated to be hydrophilic so that liquids will pass through the topsheet 24 more quickly. This reduces the likelihood that body exudates will flow from the topsheet 24 rather than being drawn through the topsheet 24 and absorbed in the absorbent core. The topsheet 24 may be rendered hydrophilic by treating it with a surfactant. Suitable methods of treating the topsheet 24 include spraying and immersing the material with a surfactant. This treatment and hydrophilicity are discussed in more detail in U.S. Patent 4,988,344.

A variety of manufacturing techniques may be used to produce the topsheet 24, for example, the topsheet 24 may be a nonwoven web of fibers. When the topsheet 24 consists of a nonwoven web, the web may be bonded by interweaving, carding, wet laid, meltblown, hydroentangled, a combination of the above or the like. Especially preferred is the topsheet 24 carded and thermally bonded by means well known to those skilled in the art of fabric technology. A particularly preferred topsheet 24 comprises staple length polypropylene fibers having a denier yarn weight of about 2.2. The term "staple-length fibers" as used herein refers to fibers having a length of at least 15.9 mm. Preferably, the topsheet 24 has a basis weight of from about 18 to about 25 g / m ² . A suitable topsheet 24 is manufactured by Veratec, Inc., Division of the Intemational Tapper Company, of Walpole, Massachusetts, USA under the designation P-8.

Preferably, the chassis assembly 22 further comprises resilient leg cuffs 30 to provide improved containment of liquids and other body exudates. Each elastic leg cuff 30 may include several different embodiments for limiting leakage of body exudates in the leg regions. (These elastic leg cuffs may be and are sometimes referred to as leg loops, side flaps, barrier cuffs, or elastic cuffs). U.S. Patent 3,860,003 discloses a disposable diaper that provides a leg flap with a side flap and one or more resilient members to provide a resilient leg cuff (sealing cuff). U.S. Pat. No. 4,909,803 discloses a disposable diaper having "erect" elastic flaps (barrier cuffs) for improved sealing in the leg regions. U.S. Patent No. 4,695,278 discloses a disposable diaper having double cuffs comprising a sealing cuff and a barrier cuff. U.S. Pat. No. 4,704,115 discloses an incontinence disposable diaper or garment having side, edge, leak guarding grooves arranged to retain loose liquids within the garment. While each elastic leg cuff 30 may be arranged to be similar to any of said leg bands, side flaps, barrier cuffs or elastic cuffs described above, it is preferred that each elastic leg cuff 30 include a sealing cuff such as This is described in the above-cited U.S. Patent 4,860,003.

Each elastic leg cuff 30 is shown in Figure 1 as comprising one elastic member 31. In some embodiments, it may be desirable that each elastic leg cuff 30 comprise a plurality of elastic members 31. These elastic members 31 extend beyond the waist edge 59 of the absorbent member. of the core 28 and into the extensible waistband 32. Before use, they are opposed innermost

The elastic members 31 located on opposite sides of the absorbent core are substantially linear and substantially parallel to each other along their entire length. Prior to use, the resilient elements 31 are also aligned substantially parallel to both the side edges 58 of the absorbent core 28 and the leg edges 61 of the chassis assembly 22 along its entire length.

The dimension between the opposing innermost spring elements is substantially uniform throughout their length prior to use. The dimension between the opposing innermost elastic members is indicated by 105 in FIG. 1. The dimension between the opposing innermost elastic members is measured across the absorbent core 28 parallel to the lateral centerline 48 of the diaper. In use, the extensible waistband 32 stretches or is stretched in the lateral direction when worn or attached to the wearer. When the belt 32 is stretched in the lateral direction during use, the dimension between the opposing innermost elastic members positioned within the expanded waist increases while the remaining portion of the opposing innermost elastic members remain substantially unchanged. Thus, in use, the dimension between the opposing innermost elastic members positioned within the stretched waist is greater than the dimension between the remainder of the opposing innermost elastic members, for example, portions of the elastic members positioned so as to abut the side edges of the absorbent core.

The diaper 20 further includes an extensible waistband 32 for improved fit and retention. This extensible waistband 32 extends at least laterally outwardly from each leg edge 61 of the chassis assembly 22, and preferably longitudinally outwardly from one of the lateral edges of the chassis assembly 22. Thus, in the embodiment of Fig. 1, the extensible waistband 32 includes that portion of diaper 20 which extending at least from the lateral edge 60 of the chassis assembly 22 in the second waist region 42 to the end edge 46 of the diaper 20 and is intended to be positioned adjacent the waist of the wearer. Although the disposable diaper of the present invention can be assembled with an extensible waistband 32 attached to each lateral edge 60 of the chassis assembly 22. discussion of the extensible waistband 32 focuses on diapers having a single extensible waistband constructed in accordance with the present invention to form a "diaper" T “. Further, although the belt or any of its constituent elements may be assembled as an extension of other diaper elements such as the backsheet 26 or the topsheet 24, or both (as shown in U.S. Pat. No. 3,860,003), belt 32 will be described with respect to a particularly preferred embodiment in which the belt is a separate member attached to the chassis assembly 22.

The waistband 32 provides an extensible fit that provides a more comfortable and adaptable fit by providing a comfortable fit to the wearer at the beginning and remaining so throughout the wearer long enough after the diaper has been filled or loaded with exudates, since the extensible waistband allows the diaper sides to expanded and contracted without the use of additional resilient materials. Further, the extensible waistband exerts and maintains supporting forces (tensions) that increase the development and maintained by the closure system to maintain the diaper 20 on the wearer and thereby improve fit of the diaper around the wearer's waist. The extensible waistband further provides for more efficient fit of the diaper 20, because even if the diaper is pulled further away on one side (side portion) of the extensible waistband than on the other (asymmetrically), the diaper 20 will "self-adjust" during wear. Although the diaper 20 of the present invention preferably has an extensible waistband 32 that is disposed in the second waist region 42; alternatively, the diaper 20 may be provided with an extensible belt arranged in the first waist region 40 or a belt arranged in both the first waist region 40 and the second waist region 42.

As shown in FIG. 1, the extensible waistband 32 has a central waistband panel 56 and a pair of side panels 57, each disposed on each side of the central waistband panel 56. The central waistband panel 56 is that portion of the waistband 32 between the leg edges 61. Thus, this central waist panel 56 is also terminating or having the same width as the width of the chassis assembly 22 in the lateral edge 60. The side panels 57 extend laterally outwardly from the central waist panel 56 beyond the foot edges 61 of the chassis assembly 22. the advantages of adapting and retaining the belt as discussed herein, at least the side portions 57 of the belt 32 must be extensible. In the particularly preferred embodiment shown in FIG. 1, the central waistband panel 56 as well as the side panels 57 are preferably

Expandable to provide a generalized waistband adaptable to the wearer to provide the benefits of adaptation and retention.

The belt 32 may have a variety of different sizes, shapes, and configurations and may be constructed of a variety of different materials. For example, the belt may be formed from one or more separate portions comprising portions of a set of chassis 22 that are joined together to form a coordinated whole, or the belt 32 as shown in Fig. 1 may comprise a single piece of material. The belt may also have a variety of widths and lengths to ensure adaptation to different wearer sizes or for cost or retention reasons. Further, the shape of the belt can vary considerably from complex curves and angles to a simple rectangular shape as shown in Figure 1.

Although the belt 32 may be comprised of a variety of different extensible materials known in the art, for reasons of operation and cost, the belt is preferably constructed of a web of structural as resilient film. The term "material" here means a layer-like material comprising a single layer of material or a laminate of two or more layers.

Giant. 5 illustrates a particularly preferred embodiment of a structural as resilient film 52 of the present invention, composed of a single layer of molded polymer material. The structural, resilient film 52 is shown in its substantially untensioned condition. The belt has two central axes, a longitudinal axis 1 and a transverse or lateral axis t, which is generally perpendicular to the longitudinal axis. The web is preferably composed of substantially linear low density polyethylene (LLDPE), although it may also contain other polyolefins such as low density polyethylene (LDPE), ultra low density polyethylene (ULDPE), high density polyethylene (HDPE), or polypropylene and / or or mixtures thereof with the above and other materials. Examples of other suitable polymeric materials include, but are not limited to, polyester, polyurethanes, compostable or biodegradable polymers, and breathable polymers.

Referring to Figures 5 and 5A, a web of structurally resilient film comprises a "stretchable network" of different regions. As used herein, the term "stretchable network" refers to an interconnected and interdependent group of regions that have the ability to be stretched to a useful degree in a predetermined direction, thereby providing the structural film web with a resilient behavior in response to applied and subsequently released extension. The strainable network comprises at least a first region 64 and a second region 66. The SELF web 52 comprises a transition region 65 that is at the interface between the first region 64 and the second region 66. This transition region 65 will similarly exhibit a complex combination of behavior of both the first and second regions. . It is understood that each embodiment of the present invention will have transition regions, but a particularly preferred embodiment of the present invention is generally defined by the behavior of the web material in different regions (e.g., the first region 64 and the second region 66). Thus, the following description of the present invention will only address the behavior of the web material in the first regions and the second regions, since it is not significantly dependent on the complex behavior of the web material in the transition regions 65.

The web of structurally flexible film 52 has a first surface and an opposed second surface. In a particularly preferred embodiment shown in Figures 5 and 5A, the strainable network comprises a plurality of first regions 64 and a plurality of second regions 66. The first regions 64 have a first axis 68 and a second axis 69, wherein the first axis 68 is preferably longer than the second axis 69 The first axis 68 of the first region 64 is substantially parallel to the longitudinal axis of the web of the structural film of elastic film 52, while the second axis 69 is substantially parallel to the transverse axis of the web of the structural film of elastic film 52. i.e., the width of the first region) is from about 0.0254 cm to about 1.27 cm, and more preferably from about 0.0762 cm to about 0.635 cm. The second regions 66 have a first axis 70 and a second axis 71. The first axis 70 is substantially parallel to the longitudinal axis of the web of structurally resilient film 52, while the second axis 71 is substantially parallel to the transverse axis of the web of structurally resilient film 52. preferably, the second axis of the second region (i.e., width of the second region) is from about 0.0254 cm to about 5.08 cm, and more preferably from about 0.317 cm to about 2.54 cm. In the particularly preferred embodiment of FIG. 5, the first 64 and second 66 regions are substantially linear, extending

292297 B6 continuously in a direction substantially parallel to the longitudinal axis of the web of structurally resilient film 52.

The first region 64 has a modulus of elasticity E1 and a cross-sectional area A1. The second region 66 has a modulus of elasticity E2 and a cross-sectional area A2.

In the illustrated embodiment, a portion of the web of the structural film of elastic film 52 has been "shaped" such that the web of the structural film of elastic film 52 exhibits a resistive force along an axis substantially parallel to the longitudinal axis of the web of the structural film of elastic film. when subjected to an applied axial extension in a direction substantially parallel to the longitudinal axis. As used herein, the term " shaped " refers to the formation of a desired structure or geometry on a web of structurally resilient film that substantially retains the desired structure or geometry; when not subjected to any external applied extensions or forces. the web of a structural, resilient film of the present invention is comprised of at least a first region and a second region, the first region being visually different from the second region. this refers to the features of the structural film of the elastic film, which are readily recognizable to the naked eye when the structural film of the elastic film, or the articles with the treated structural film of the elastic film, are subjected to normal use. Preferably, the first region has a "surface path length" shorter than the second region, measured parallel to the predetermined axis when the material is in the non-tensioned state. As used herein, the term "surface path length" refers to measurements along the topographic surface of the subject region in the direction of a predetermined axis. The method for determining the surface path length of the respective regions can be found in the section entitled "Test Methods" given in the following sections of this description.

Methods of forming a web of structural as resilient film include, but are not limited to, embossing plates or rollers, thermoforming, high pressure hydraulic forming, or casting. Although the entire portion of the web of structurally resilient film 52 has been subjected to a forming operation, the present invention can also be practiced by subjecting only a portion thereof, for example, a portion of the backsheet 26 of the diaper.

In a particularly preferred embodiment shown in Figures 5 and 5A, the first regions 64 are substantially planar, i.e., the material within the first region 64 is substantially in the same condition before and after the forming step through which the web of structurally resilient film 52 has passed. The second regions 66 comprise a plurality of raised rib-like elements 74. These rib-like elements 74 may be punched or drawn or formed by a combination of these techniques. The rib-like elements 74 have a first or major axis 76 that is substantially parallel to the transverse axis of the web of structurally resilient film and a second or minor axis 77 that is substantially parallel to the longitudinal axis of the web of structurally resilient film 52. The rib-like elements 74 are at least equal to and preferably longer than the second axis 77. Preferably, the ratio of the lengths of the first axis 76 to the second axis 77 is at least about 1: 1, or greater, more preferably at least 2: 1 or greater.

The rib-like elements 74 in the second region 66 may be separated from each other by unformed surfaces, substantially non-aligned, unstretched, or simply formed as intermediate surfaces. The rib-like elements 74 are preferably adjacent to each other and are divided by an unformed area of less than 0.254 cm, measured perpendicular to the major axis 76 of the rib-like element 74, and more preferably, the rib-like elements 74 are continuous without any un-shaped areas.

The first region 64 and the second region 66 each have a certain protruding path length. As used herein, the term protruding path length refers to the shadow length of a region that would be thrown by parallel light. The protruding path length of the first region 64 and the protruding path length of the second region 66 are equal to each other.

The first region 64 has a surface path length L1 less than the surface path length L2 of the second region 66, measured topographically in a direction parallel to the longitudinal axis of the web as a structural

The elastic film 52 while the web is of a structural, like, elastic film is in an untensioned condition. More preferably, the surface path length of the second region 66 is at least about 15% greater than the surface path length of the first region 64, more preferably at least about 30% greater the surface path length of the first region, and most preferably at least about 70% greater than the surface path length. first region. Overall, the greater the length of the track over the surface of the second region, the greater will be the elongation of the web of a structurally resilient film before facing a sudden increase in force.

What makes a web of structurally resilient film particularly well suited for use on belt 32 is that it exhibits a modified "Poisson lateral contraction effect" that is substantially smaller than the same phenomenon of an otherwise identical, unformed base web of similar material composition. As used herein, the term "Poisson lateral contraction effect" describes this lateral contraction behavior of a material that is subjected to an applied elongation. A method for determining the Poisson lateral contraction effect of a material is found in the section entitled Test Methods, which is set forth in the following sections of this specification. Preferably, the Poisson lateral contraction effect of the structural film of a flexible film of the present invention is less than about 0.4 when the structural film of a flexible film is exposed to a relative elongation of about 20%. Preferably, the structural-like flexible film web exhibits a Poisson lateral contraction effect of less than about 0.4 when the structural-like flexible film web is subjected to a relative elongation of up to about 40, 50 or even 60%. The Poisson lateral contraction effect of the webs of the present invention is determined by the amount of web material occupied by the first and second regions, respectively. As the area occupied by the first region of the web of structurally resilient film increases, the Poisson lateral contraction effect also increases. Conversely, as the area occupied by the second region of the web of structurally resilient film increases, the Poisson lateral contraction effect decreases. Preferably, the percentage of the web area of the web of the structural as resilient film occupied by the first region is from about 2% to about 90%, and more preferably from about 5% to about 50%.

Prior art web materials having at least one layer of elastomeric material will generally have a large Poisson lateral contraction effect, i.e., will "taper" as they stretch in response to the applied force. The webs of the structural-like elastic film of the present invention may be designed to mitigate, if not substantially eliminate, the Poisson lateral contraction effect.

For strips of structurally flexible film 52, the direction of the applied axial extension D indicated by the arrows 80 in FIG. 5 is substantially perpendicular to the first axis 76 of the rib-like elements 74. The rib-like elements 74 may be designed or geometrically deformed in a direction substantially perpendicular a first axis 76 to allow the web of the structural, resilient film 52 to extend.

FIG. 6 is a graph of the resistive force / elongation curve 720 of a shaped web of a polymeric web of a structural as resilient film of the present invention, along with a curve 710 for a base web material, i.e. not containing first and second regions similar to the web Ingredients. In particular, samples of polymeric sheet materials are comprised essentially of linear low density polyethylene, about 0.00254 cm thick, sold under the designation Sample 1401, available from Clopay Corporation of Cincinnati, Ohio, USA. The method for generating the resistive force / elongation curves can be found in the section entitled "Test Methods" given in the following sections of this description. From the curve of the resistive force and elongation 720, it can be seen that the initial substantially linear phase I of the lower force and elongation dependence, denoted 720a, has a transition zone denoted 720b. which indicates a collision with a step increase in force, and a substantially linear phase Π, denoted by 720c, which exhibits essentially behavior with the existence of a higher force dependence and elongation.

As shown in FIG. 6, a web of a structural film of elastic film having a stretchable mesh exhibits different biasing behavior in two phases, stretching in a direction parallel to the longitudinal axis of the web of a structural film of elastic film. The resistive force exerted by the web of a structurally resilient film at a given elongation is significantly less in the phase I region (720a).

In addition, the resistive force exerted by the web of a structurally resilient film increases and approximates the resistive force exerted by the base web. The resistance force applied to the applied elongation for the phase I region of the web of structural film of elastic film is generated by deformation at the molecular level of the first region of the web of structural film of elastic film and geometric deformation of its second region. This is in contrast to the resistive force applied to the applied elongation that is produced by the base band as shown in curve 710 in Figure 6, which is the result of the deformation at the molecular level of the entire strip. The web materials of the present invention can be designed to provide substantially any phase I resistive force that is less than that of the base web web by adjusting the percentage of web surface that is comprised of the first and second regions. The Phase I force and elongation behavior can be controlled by adjusting the width, cross-sectional area and pitch of the first region, and the composition of the base band.

Referring to Fig. 5B, when the structural film of elastic film 52 is subjected to the applied axial elongation D, indicated by the arrows 80 in Fig. 5, the first region 64 with shorter surface path length, L1 generates most of the initial resistive force P1 as a result of deformation at the molecular level due to the applied elongation corresponding to phase I. While in phase I the rib-like elements 74 in the second region 66 undergo geometric deformation or straightening and offer minimal resistance to the applied elongation, the transition zone (720b) between phases I and Π becomes rib-like the elements 74 are aligned with the applied elongation, i.e. the second region shows a change from geometric deformation to molecular-level deformation. This is the beginning of a sudden increase in power. In phase Π, as seen in Fig. 5C, the rib-like elements 74 in the second region 66 are substantially aligned with the plane of the applied elongation (i.e., the second region that has reached its geometric deformation limit) and begin to resist further elongation through deformation at the molecular level. The second region 66 now contributes, as a result of molecular-level deformation, a second resistive force P2 to a further elongation. Resistance forces to elongation at phase Π from both the molecular deformation of the first region 64 and the molecular deformation of the second region 66 provide a total resistive force PT that is greater than the resistive force shown in phase I provided by the molecular level deformation of the first region 64 and geometric deformation of region 66. Accordingly, the slope of the force-elongation curve in phase Π is significantly greater than the slope of this curve in phase I.

The resistive force P1 is substantially greater than the resistive force P2 when (L1 + D) is less than L2. When (L1 + D) is less than L2, the first region 64 provides an initial resistance force P1, generally according to the following equation:

(AlxElxD)

P1 = ----------- LI

When (L1 + D) is greater than L2, the first and second regions provide a combined total resistive force PT relative to the applied elongation D generally according to the following equation:

(AlxE1xD) (A2xE2x / L1 + D-L2 /)

PT = --------- + ----------------- L1 L2

The maximum elongation occurring in phase I is said to be useful as a stretch of the web of a structural, like, elastic film. This usable extension corresponds to the distance during which the second region undergoes geometric deformation. The applicable stretch can be effectively determined by examining the force-elongation curve 720 as shown in Figure 6. The approximate point at which inflection occurs in the transition zone between phase I and phase Π is the percentage elongation point representing the applicable stretching. Range of use

The expansion may vary from about 10% to 10% or more; this elastic response range is often found to be of interest in disposable absorbent articles and can be to a large extent in that the length of the surface path L2 in the second region 66 exceeds the length of the surface path L1 in the first region 64 and the base film composition. The term extensible stretch is not intended to imply a limit of the elongation to which a web of a structural, resilient film of the present invention can be subjected, since there are applications where the extensibility beyond the extensible stretch is desirable.

Curves 730 and 735 of Figure 7 illustrate the elasticity of the hysteresis behavior exhibited by the structural-like elastic film web of the present invention, which is generally similar to the structural-like elastic film web used to form the curve 720 of Figure 6. the film was investigated for elastic hysteresis behavior at elongation 60%. Curve 730 represents the response to the applied elongation and release during the first cycle, and curve 735 represents the response to the applied elongation and release during the second cycle. Figure 7 shows the relative decrease in force during the first cycle 731 and the permanent deformation in percent 732. Note that a significant reversible elongation or useful elasticity is exhibited at relatively low forces even after multiple cycles, i.e., a structural-like belt the flexible film can easily stretch to a considerable degree. A method for examining elastic hysteresis behavior can be found in the section entitled "Test Methods" in the following section of this description.

When the web of structurally resilient film is subjected to an applied elongation, the material behaves as if resiliently. When it extends in the direction of the applied elongation and does not return to its substantially untensioned state once the applied elongation is removed, unless the web of structurally resilient film is stretched beyond the compliance point. The web of structurally resilient film may undergo multiple cycles of applied elongation without losing its ability to substantially return to its original state. Accordingly, the web of structurally resilient film has the ability to return to its substantially untensioned state when the applied elongation or force is removed.

While the web of structural film of elastic film can be easily and reversibly stretched in the direction of the applied axial extension, in a direction substantially perpendicular to the first axis of the rib-like elements, the web of structural film of elastic film does not expand as easily as in the direction substantially parallel to the first axis of these webs. ribbed elements. The formation of the rib-like elements allows these rib-like elements to geometrically deform in a direction substantially perpendicular to the first or major axis of the rib-like elements while requiring substantially deformation at a molecular level to expand in a direction substantially parallel to the first axis of the rib-like elements.

The amount of force applied to stretch the web of structurally resilient film depends on the composition and cross-sectional area of the web forming the web of structurally resilient film and the width and width and pitch of the first regions, with narrower and wider first regions requiring smaller the applied stretching forces to achieve the desired elongation. The first axis (i.e. length) of the first regions is preferably greater than the second axis (i.e. width) of the first region with a particularly preferred length to width ratio of about 5: 1 or greater.

The depth and number of the rib-like elements may also be varied to control the useful stretch of the web of a structurally resilient film. The usable stretch increases if, for a given frequency of the fin elements, the height or degree of deformation imparted to the fin elements is increased. Similarly, the available stretch increases if the number or frequency of the rib-like elements is increased for a given height or degree of deformation.

Although the entire web of structurally resilient film comprises a stretchable web of the first and second regions, the present invention may also be practiced such that only specific portions of the web of structurally resilient film of the first and second regions. For example, only the side panels 57 of the belt 32 may comprise separate strainable nets. Thus, all or part of the extensible belt may comprise a strainable network comprised of first and second regions to provide the extensible belt.

A belt having a controlled stretching response along a predetermined axis when subjected to an axial extension.

Also, the web of structural film of elastic film need not be extensible only in a direction parallel to the lateral axis of the diaper as shown in FIG. 1. For example, the longitudinal axis and the transverse axis of the web of structural film of elastic film may be arranged at an angle to the longitudinal axis or lateral axis. Thus, a web of a structural, resilient film would axially extend along a line at an angle to the lateral axis of the diaper. Preferably, this angle is between about 0 and about 30 in the diapers of the present invention. Further, portions of the web of a structurally flexible film may have different angles of extensibility. For example, in the side panels, the portion of the side panel closest to the end edge of the diaper, i.e., the waist panel, may be extensible in a direction parallel to the lateral axis of the diaper, not parallel to the direction of extensibility of the waistband so that it is arranged at an angle to the lateral axis. This multidirectional structural elastic film component can provide improved waist and leg adaptability.

FIG. 8 illustrates an apparatus 400 used to form a web of a structural, resilient film 52 shown in FIG. 5. The apparatus 400 includes plates 401 and 402 and 402 comprising a plurality of interlocking teeth 403 and 404, respectively. pressed together to form the base film 406.

It can be seen in Fig. 9 that both plates 401 and 402 have a longitudinal axis 1 and a transverse axis t that is substantially perpendicular to this longitudinal axis. The plate 401 comprises regions with teeth 407 and regions with grooves 408 that both extend substantially parallel to the longitudinal axis of the plate 401. Inside the regions with teeth 407 of the plate 401 there are a plurality of teeth 403. The plate 402 includes teeth 404 that fit into the teeth 403 of the plate. 401. When the base film 406 is formed between the plates 401 and 402, portions of the base film 406 that are located within the groove regions 408 of the plate 401 and the teeth 404 on the plate 402 remain undeformed. These regions correspond to the first regions 64 of the web of structural-like elastic film 50 shown in FIG. 5. The portions of the base film 406 disposed between the regions with the teeth 407 of the plate 401 and the teeth 404 of the plate 402 are incrementally and plastically shaped to form a ribbed the elements 74 in the second regions 66 of the ribbed strip of a structurally resilient film 52.

The molding process can be performed in a static mode where one discrete base film portion is deformed at a time. An example of this method is shown in FIG. 10. The static press, generally designated 415, comprises an axially movable plate or portion 420 and a stationary plate 422. The plates 401 and 402 are attached to the portions 420 and 422, respectively. the base film 406 is sandwiched between the plates 401 and 402. These plates are then brought together under a pressure generally referred to as P. The upper plate 401 is then axially lifted away from the plate 402, thereby allowing the shaped polymer material to be removed from the space between the plates 401 and 402.

Giant. 11 is an example of a dynamic press for intermittently contacting a moving web and shaping the base material 406 into a shaped web similar to the web of structurally resilient film 52 of FIG. 5. The polymer film 406 is supplied between the sheets 401 and 402 in the direction generally indicated by arrow 430. 401 is secured to a pair of rotatably mounted arms 432 and 434 that move in a clockwise direction, which moves the plate 401 in a similar clockwise movement. The plate 402 is coupled to a pair of rotary arms 436 and 438 that move in a counterclockwise direction, advancing the plate 402 in a clockwise direction. Thus, as the strip 406 moves between the plates 401 and 402 in the direction indicated by the arrow 430. a portion of the base film is formed between the plates and then released so that the plates 401 and 402 can be rolled back, gripping and deforming another portion of the base film 406. it has the advantage of allowing any patterns of any complexity to be shaped in a continuous process, for example one-way, two-way and multidirectional patterns.

-14EN 292297 B6

The dynamic press of FIG. 11 could be used on the finished absorbent article to form the stretchable webs into the finished product. For example, all or parts of the finished absorbent article could be positioned between the plates 401 and 402 to form a stretchable mesh in all layers of the absorbent article.

Yet another method of forming a base material into a web of a structurally resilient film is vacuum forming. An example of a vacuum forming method is given in U.S. Pat. No. 4,342,314. Alternatively, the web of a structural, resilient film of the present invention can be shaped hydraulically in accordance with U.S. Pat. No. 4,609,518. in the description by reference.

Fig. 12 shows yet another apparatus, generally designated 500, for forming a base film into a shaped web of a structurally resilient film. The apparatus 500 comprises a pair of rollers 502 and 504. The roller 502 comprises a plurality of toothed regions 506 and a plurality of groove regions 508 that extend substantially parallel to the longitudinal axis of the extending roller 502. The toothed regions 506 comprise a plurality of teeth 507. When the base sheet passes between the interlocking rollers 502 and 504, the flute regions 508 leave portions of the sheet unformed, thereby forming the first regions of the web from the structural as resilient sheet 52 of Figure 5. the films passing between the toothed regions 506 and the teeth 510 will be shaped by the teeth 507 and 507 respectively. 510, thereby producing rib-like elements in the second regions of the web from a structural, like, elastic film 52.

Alternatively, the cylinder 504 may comprise a soft rubber. When the base film extends between the toothed roller 502 and the rubber roller 504, it is mechanically formed into a pattern formed by the toothed roller 502. The film within the groove regions 508 will remain undeformed while the film inside the toothed regions 506 will be formed to form rib-like elements in the other regions.

FIG. 13 illustrates an alternative apparatus, generally designated 550, for forming a base film into a web of a structural, resilient film of the present invention. The apparatus 550 comprises a pair of rollers 552 and 554. Both rollers 552 and 554 have a plurality of toothed regions 556 and groove regions 558 extending around the periphery of rollers 552 and 552, respectively. 554. When the base film passes between the interlocking rollers 552 and 554, the flute regions 558 leave portions of the film unformed, while portions of the film passing between the toothed regions 556 will be formed into rib-like elements in the second regions 66.

The web material of the present invention may be of polyolefins such as polyethylenes, including linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ultra-low density polyethylene (ULDPE), high density polyethylene (HDPE) or the above, and mixtures thereof and above materials. Examples of other suitable polymeric materials that may also be used include, but are not limited to, polyester, polyurethanes, compostable or biodegradable polymers, heat shrinkable polymers, thermoplastic elastomers, metallocene catalyst based polymers (e.g., INSITE® available from INSITE®). from Dow Chemical Company and EXXACT® from Exxon) and breathable polymers. The web materials may also be comprised of synthetic woven, synthetic knit, nonwoven, apertured film, macroscopically expanded three-dimensional shaped film, absorbent or fibrous absorbent material, foam-filled composite or laminates, and / or combinations thereof. Woven materials can be made by the following methods without limiting them: yarn weaving, yarn splicing, melt blowing, carding and / or air laying or calendering, with the interconnected yarn with loosely bonded fibers being a particularly preferred embodiment.

Although the web of a structurally resilient film has been described as a single layer of substantially flame polymeric film, the present invention can be practiced equally well with other base materials or laminates of materials. Examples of other base materials from which it can be produced

The web of the structural, resilient film of the present invention includes two-dimensional apertured film and macroscopically expanded, apertured formed film. Examples of macroscopically expanded, three-dimensional apertured films are disclosed in U.S. Patents 3,929,135, 4,324,246, 4,463,045, and 5,006,394. Examples of other suitable base materials include composite structures or laminates of polymeric films, nonwoven materials, and polymer films and nonwovens. Laminates of polymeric films and nonwoven materials may comprise absorbent or fibrous absorbent materials, or other blends. Other reinforcement elements may also be added for greater strength and restoration.

Also, base materials comprising laminates of apertured films and nonwoven materials can be used, breaking the bond between a plurality of nonwoven fibers to slightly project the apertures through the apertured film apertures.

In some embodiments, it may be desirable for the web of structurally resilient film to exhibit a degree of bulkiness. Ways of providing increased bulkiness are by using laminates of polymeric films with highly expanded nonwoven materials and laminates with multiple layers of nonwoven materials. Other methods of forming the volume include forming a single layer of polymeric film by the method of the present invention, followed by prestretching the film and subsequently applying the nonwoven material to one or both sides while the polymeric film is in a prestressed state. When the tension is released, the nonwoven material forms a wrinkle that gives the material bulk. Yet another method for producing bulky laminates is by molding individual layers of a polymer film with the method of the present invention followed by lamination of multiple layers of these materials. Three-dimensionally apertured films which have been formed using the method described herein also provide good bulk in the laminate structure.

Other materials that may be subjected to the deformation processes disclosed herein to produce belts that behave as if resiliently in the direction of applied force include polymer foam and thermally bonded, air laid fibrous structures.

Giant. 14 depicts the force and elongation behavior for both the base web conforming to curve 830 and the preformed web of structural like resilient film conforming to curve 840, both of which are comprised of a laminate of a Clopay polyethylene film layer 1,401 glued with a hot melt adhesive available from Findley Adhesives in Wauwatosa, Wisconsin, USA under the designation Sample 2301, to a nonwoven layer made essentially of polypropylene fibers as available from Veratec of Walpole. in Massachusetts, USA under the designation P1. As can be seen from curve 840, there is an initial substantially linear phase I with lower force and elongation, denoted 840a, a transition zone denoted 840b, and a substantially linear phase Π denoted 840c. With regard to this laminate web, it is necessary to note the distinct biphasic behavior with lower force in the preformed web of structural as resilient film formed in the first phase I (840a) by a combination of molecular-level deformation in the first region and geometric deformation of the second region and then phase Π (840c) of molecular-level deformations in both the first region and the second region as shown in curve 840, as compared to the molecular-level deformation at the base band as shown in curve 830. Curves 850 and 855 Fig. 15 shows the elastic hysteresis behavior of the shaped web material used to form the curve 840 of Fig. 14 examined at 60% elongation. Curve 850 represents the response to the applied and released elongation during the first cycle, and curve 855 represents the response to the applied and released elongation during the second cycle. FIG. 15 shows the relative force copes during the first cycle 851 and the percent permanent deformation of the web after the first cycle 852. Note that this laminate web exhibits a very significant elastic return to the observed elongation range over multiple cycles.

In a particularly preferred embodiment of the present invention, as shown in FIG. 2, the web of structurally resilient film comprises a three layer laminate comprising an inner layer 53, an outer layer 55, and a planar layer 54. The inner layer 53 is preferably a nonwoven material. as before

The material P-8 is described. The outer layer 55 is preferably a base polymer film as described herein with reference to FIG. 5. The backing layer 54 is preferably a shaped film such as DRI-WEAVE as sold by The Procter & Gambie Company of Cincinnati. in Ohio, USA. Alternatively, the backing layer 54 may be eliminated to form a low cost two-layer laminate of a nonwoven material and a base polymer film. Additionally, a nonwoven layer may be added over the outer layer 55 to provide a softer feel to the outside of the belt. These laminates may be bonded by any of a number of bonding methods known to those skilled in the art. Such bonding methods include, but are not limited to, heat bonding, adhesive bonding (using any of a number of adhesives including, but not limited to, spray adhesives, hotmelt adhesives, latex based adhesives and the like), ultrasonic bonding and extrusion lamination, the polymeric film is cast directly onto a nonwoven substrate and while still in a partially molten state, it is attached to one side of the nonwoven or where the meltblown nonwoven is directly attached to the polymer web.

The belt 32 is attached to the chassis assembly 22 by the belt fastener 50. The belt fastener 50 may include any known attachment means as discussed herein, including adhesive, heat seal, pressure seal, ultrasonic seal, dynamic mechanical seal, or a combination thereof. Preferably, the web fastener is an adhesive, preferably an open pattern web of adhesive fibers as described herein. The waistband 32 is preferably directly attached to the chassis assembly 22 by an inner layer 53 directly attached to the backsheet 26. Alternatively, the waistband 32 may be attached between the topsheet 24 and the backsheet 26, among other diaper elements 20, or directly to other diaper elements, including, for example, directly attaching the outer layer 55 to the topsheet 24.

The diaper 20 is also preferably provided with a closure system for fastening the diaper to the wearer. While the closure system may take many forms of arrangement, such as adhesive tape tabs, mechanical closure tape tabs, fixed position fasteners, or any other closure means known in the art, as shown in Figure 1, closure the system preferably includes an adhesive tape tab fastening system comprising a pair of tabs 34 and a zone for applying them (not shown) located in the first belt region 40 of the chassis assembly ΎΣ. Examples of suitable adhesive tape fastening systems are described in U.S. Pat. Nos. 3,848,594 and 4,662,875. Examples of other fastening systems, including mechanical fastening systems, useful in the present invention are disclosed in U.S. Patents 4,869,724, 4,848,815, and point. a fastening system is disclosed in U.S. Patent No. 5,242,436.

The diaper 20 is preferably worn by a wearer by placing one of the waist regions, preferably the second waist region 42, under the wearer's back and inserting the remainder of the diaper between its legs so that the second waist region 40, preferably the first waist region 40 is positioned in front of the wearer. . Then, the tab portions of the tape tabs 34 are released from the free portion. The diaper then wraps the extensible waistband 32 around the wearer while still clutching the tab portion. The extensible belt 32 is typically expanded and tensioned during this operation to accommodate the size and shape of the wearer. The strap tab 34 is attached to the stitching zone on the chassis assembly 22 to effect side closure. This procedure is then repeated with the second tape tab. By attaching the two tape tabs 34 to the stitching zone on the chassis assembly 22, a three-dimensional garment with closed sides having a pair of leg openings and a belt opening is formed. Thus, the diaper is closed on the wearer and the waistband 32, composed of a web of a structurally resilient film, provides the benefits of adaptation and retention described herein.

Alternatively, the belt may be provided with a closure system that allows the side panels to be joined together beforehand. The diaper then places the chassis assembly between the wearer's legs and attaches the chassis assembly to the belt layer.

A number of young children were measured to determine their characteristic size for growth.

This characteristic dimension for stature refers to the distance from the baby's navel over

- 17CZ 292297 B6 crotch region (ie between the legs of a small child while avoiding the genital region) to the cross. Measurements have been made on many young male and female children and the mean size of this distance from the navel to the cross is shown in the following table.

Table I

Characteristic size for small children (Size from navel to cross)

Weight [lb] Weight [kg] Average characteristic dimension [mm] 5.5 2.5 200 7.5 3.4 222 9.5 4.3 250 11.5 5.2 294 13.5 6.1 314 15.5 7.0 318 17.5 7.9 327 19.5 8.8 332 21.5 9.8 345 23.5 10.7 356 25.5 11.6 364 27.5 12.5 374 29.5 13.4 380 31.5 14.3 385 33.5 15.2 397 35.5 16.1 400 37.5 17.0 415 39.5 17.9 417 41.5 18.8 432 43.5 19.7 434 45.5 20.6 443

In Table I, young children were grouped according to their weight, measured in pounds. The weight of each group of young children shown in Table I relates to a certain range of baby weights. For example, a weight of 5.5 lbs (2.5 kg) corresponds to a weight range of about 4.5 lbs (2.05 kg) to about 1.5 lbs

6.4 lb (2.91 kg), and a weight of 7.5 lb (3.41 kg) corresponds to a weight range of about 6.5 lb (2.95 kg) to about 8.4 lb (3.82 kg) . These children's pounds weights were then converted to kilograms.

For comparative purposes, a series of different, commercially available disposable 20 diaper products, designated Sample A to F, and a disposable diaper of the present invention, designated Sample Q, were measured.

-18EN 292297 B6

Table H

Plena model

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index 8 to 14 (3.6 to 6.4) 314 34 185 108.9 83 850 267.0 16 to 24 (7.3 to 10.9) 356 48 375 135.9 110 295 309.8 22 to 35 (10 to 15.9) 400 57 000 142.5 128 900 322.3

Table ΠΙ

Plena model B

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index 12 to 18 (5.4 to 8.2) 327 41 280 162.2 98 040 299.8 16 to 24 (7.3 to 10.9) 356 48 375 135.9 113 520 318.8 22 to 35 (10 to 15.9) 400 57 600 144.0 131 600 329.0

Table IV

Plena model C

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index Up to 14 (up to 6,4) 314 48 375 154.1 81 270 258.8 16 to 24 (7.3 to 10.9) 356 61 275 172.1 114165 320.7 22 to 35 (10 to 15.9) 400 70 700 176.8 131 300 328.3

-19GB 292297 B6

Table V

Plena model D

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index 8 to 14 (3.6 to 6.4) 314 38 802 123.6 89 655 285.5 16 to 28 (7.3 to 12.7) 374 49 039 131.1 130 290 348.4 21 to 37 (9.5 to 16.8) 415 56 500 136.1 126 000 303.6

Table VI

Plena model E

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index 12 to 18 (5.4 to 8.2) 327 49 665 151.9 101 265 309.7 16 to 25 (7.3 to 11.3) 364 50 310 138.2 110 940 304.8 22 to 35 (10 to 15.9) 400 55 900 139.8 126 600 316.5

Table VII

Plena model F

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absoipability index Diaper area [mm ² ] Adjustment index up to 14 (up to 6,4) 314 41 280 131.5 79 335 252.7 12 to 24 (5.4 to 10.9) 356 49 665 139.5 110 295 309.8 22 to 35 (10 to 15.9) 400 63 500 158.8 123 400 308.5

-20EN 292297 B6

Table Vm

Plena pattern Q

Diaper size [lb] (kg) Maxim, navel-cross size [mm] Absorbent core area [mm ² ] Absorption index Diaper area [mm ² ] Adjustment index 8 to 16 (3.6 to 7.3) 318 24 923 78.4 74 820 235.3 16 to 26 (7.3 to 11.8) 364 26 993 74.2 84 495 232.1 22 to 38 (10 to 17.2) 415 34 202 82.4 90 864 218.9

Referring to Tables Π to Vin, the size of the diaper, the maximum dimensional growth (navel-cross) of the infant, the absorbent core area, and the diaper area are given. The size of the commercially available diapers was determined on their respective packaging. Diapers are typically made to fit children of different sizes. The diaper size is often expressed in terms of the weight of the infant. As with commercially available disposable diapers, the disposable diaper of sample Q of the present invention is designed to fit children of different sizes.

The maximum characteristic dimension of the infant's size is taken from Table I and refers to this dimension of the largest wearer who is expected to fit the diaper. The maximum characteristic dimensions of growth were determined by first finding the weight of the largest wearer, searching for the closest matching weight and the corresponding characteristic dimension of growth from Table I. For example, 181b (8.16 kg) represents the largest wearer of diapers 8 to 18 lbs. 8.16 kg). In Table I, 17.5 lb (7.94 kg) represents the closest corresponding weight up to 18 pounds (8.16 kg) and has a corresponding characteristic dimension of increase of 327 mm.

The diaper area was determined by first freezing and then removing the resilient elements from each diaper. The absorbent core was then removed from each diaper. Each diaper was then placed in its stretched state on a piece of paper having a known area and basis weight. The diaper circumference was then pulled onto paper. The tape tabs of each diaper were left in an inwardly folded or pre-user state, i.e., the state of the diaper when removed from the package, such that the tape tabs are considered to be part of the measured area of the diaper. The paper was then cut along the contour line. The cut piece of paper was then weighed. The diaper area was then calculated based on the known area and basis weight of the piece of paper prior to cutting. The same procedure was then used to calculate the area of the absorbent core for each diaper.

Tables Π to VIJI further show the resulting fit index of each diaper, which directly corresponds to the comfort and health of the wearer's skin. The term "fit index" as used herein refers to the relationship of the size of a diaper to the size of the wearer. The fit index is determined by dividing the diaper area by the characteristic dimension of growth for the outer wearer that is expected to fit the diaper. A lower diaper fit index is advantageous because less wearer skin is covered and closed by the diaper, thereby increasing the comfort and health of the wearer's skin. Conversely, a higher diaper fit index is generally less advantageous because more wearer skin is covered and closed, making the diaper less comfortable to wear because it exposes the wearer's skin to unhealthy conditions.

The diapers of the present invention are designed to fit a small child having a characteristic rise dimension ranging from about X to about Y, wherein Y represents the characteristic rise dimension of the largest wearer, or the maximum characteristic rise dimension that the diaper is expected to fit . As can be seen from the data in Tables Π to VHI, the diaper sample Q has a fit index that is less than the fit index of commercially available diapers according to

A sample of the prior art represented by the sample A? F. Because the prior art diapers have a higher fit index, they cover and seal more of the wearer's skin, making them less comfortable to wear as they expose the wearer's skin to unhealthy conditions.

The diapers of the present invention preferably have an index of fit of the diaper area to a maximum characteristic dimension of rise Y of less than or equal to about 240, more preferably less than or equal to about 238, and most preferably less than or equal to about 236.

Tables Π to VIII further show the resulting absorbency index of each diaper. This "absorption index", as used herein, refers to the relationship of the size of the absorbent core to the size of the wearer. The absorbency index is determined by dividing the area of the absorbent core by the characteristic size of the largest wearer expected to fit the diaper. A lower absorbency index is particularly advantageous because less absorbent core material is used, which makes the absorbent article more comfortable to wear. In contrast, a higher absorbency index is less preferred because more absorbent material is used, making the diaper less comfortable to wear.

The diapers of the present invention are designed to fit a child having a characteristic growth dimension ranging from about X to about Y, wherein Y represents the characteristic growth dimension of the largest wearer expected to fit the diaper. As can be seen from the data in Tables Π to VID, the diaper sample Q has an absorbency index less than the absorbency index of a commercially available diaper of Sample A to F. Because prior art diapers have a higher absorbency index, more material and are less comfortable to wear.

The diapers of the present invention preferably have an absorbency index of the absorbent core region to a maximum characteristic dimension of rise Y of less than or equal to about 95, more preferably less than or equal to about 90, and most preferably less than or equal to about 85.

Giant. 3 illustrates an alternative embodiment of the present invention wherein the belt 32 is formed from separate materials joined together. In this embodiment, each of the side portions 357 is a separate material, preferably a web of structurally resilient film 52 as described herein is joined at the edge of the foot 61 by a set of chassis 22. The central web 356 is formed by a portion of the set of chassis 22. in this embodiment, the end flap 62 formed by extending the topsheet 24 and backsheet 26 beyond the waist edge 59 of the absorbent core 28. Thus, in this embodiment, the center waistband 356 is not extensible, but the side panels 357 are formed from a web of structural as resilient film. 52.

Giant. 4 illustrates another alternative embodiment of the present invention wherein the waistband 432 is formed from a continuous web of structurally resilient film and a portion of the chassis assembly 22. In this embodiment, the web of structurally resilient film 52 extends over the entire diaper in the second waist region 42. The chassis assembly 22 is attached to a web of structurally resilient film 52 in the central waistband panel 456. While the central waistband panel 456 may be non-extensible because the components of the chassis assembly 22 are non-extensible, in a particularly preferred embodiment shown in FIG. subjected to mechanical tensioning to allow the central waistband panel 456 to have some degree of extensibility, or to methods of making a web of structurally resilient film as described herein so that the belt 432 is entirely of the web of structurally resilient film. This extensibility is shown in dashed lines in FIG. The lateral rim 60 of the chassis assembly 22 in the first waist region 40 is also provided with an elastic waistband 462 by operatively associating the elastic member 464 with the chassis assembly 22, preferably with either the topsheet 24, backsheet 26, or both, more preferably between topsheet 24 and backsheet. 26. Examples of such elastic bands are disclosed in U.S. Pat. Nos. 5,151,092 and 4,515,595. Alternatively, the lateral edge of the chassis assembly in the first region may also include a web of structurally resilient film as described herein.

-22EN 292297 B6

In an alternative embodiment of the present invention, the diaper may also be provided with ear flaps that extend laterally outward from each edge around the legs of the chassis assembly in the first waist region. The ear flaps provide a structure to which a belt can be attached to surround the wearer's legs and belt. The ear flaps may have different sizes, shapes, arrangements and materials. The ear flaps may comprise a portion of the material forming one or more diaper elements, including the topsheet 24 and the backsheet 26. Alternatively, the ear flaps may comprise a separate element or a plurality of elements attached to the diaper. Suitable materials for use in ear diapers include woven webs, nonwoven webs, films including polymeric films, foams, laminate materials including laminated films, nonwoven laminates or zero-tension laminates, elastomers, composites, structural-like elastic film webs, or any combination of these materials. The ear flaps may be attached to the chassis assembly by any means known in the art, for example, the ear diapers may be continuously or intermittently attached to the chassis assembly using heated or unheated adhesive, thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other means. known in the art.

Giant. 16 depicts another alternative embodiment of a sports pants 900 of the present invention. Sports briefs 900 include a front panel 901 and a rear panel 902 which are joined together by the side panels 903 to form a three-dimensional garment with closed sides having a pair of leg openings 904 and an opening for the belt 905. an absorbent core positioned within the outer shell. Sports pants 900 have an absorbent article area and an absorbent core area.

The side panels can take on a variety of sizes, shapes, configurations and materials. The side panels may comprise a portion of the material constituting one or more elements of the sports pant, including the topsheet 24 and the backsheet 26. Alternatively, the side panels may comprise a separate element or a plurality of elements affixed thereto. Suitable materials for use as side panels include woven webs, nonwoven webs, films including polymeric films, foams, laminate materials including laminated films, non-woven or zero-tension laminates, elastomers, composites, structural or elastic film webs, or any a combination of these materials. The side panels may be attached to the front and rear panels by any means known in the art, for example, the side panels may be continuously or intermittently attached to the front and rear panels using heated or unheated adhesive, thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or by any other method known in the art.

Methods of testing

Surface path length

The measurement of the path length of a region of formed material must be determined by selecting and preparing representative samples of each region and analyzing these samples using microscopic image analysis methods.

Samples must be selected to be representative of the surface geometry of each region. In general, transition regions should be omitted, as they normally contain features of both first and second regions. The sample to be measured is cut and separated from the study region. The "measured edge" must be cut parallel to the specified extension axis. Typically, this axis is parallel to the formed primary axis of either the first or second region. The length of the unstretched specimen of about 1.27 cm must be "marked" perpendicular to the "measured edge" if it is still attached to the material web and then cut it precisely and removed from the region of the material.

The samples to be measured are then attached to the long edge of the microscope slide. The 'measured edge' should extend slightly (approximately 1 mm) outwards from the edge of the slide. A thin layer of pressure-sensitive adhesive is applied to the leading edge of the slide to ensure proper adhesion

For highly shaped sample regions, it has been found desirable to gently stretch the sample in its axial direction (without applying significant force) while contacting and attaching the sample to the edge of the slide. This allows for better identification of the edge during image analysis, thus avoiding the possible "crumpling" of the edge portions, requiring additional interpretation analysis.

Images of each specimen shall be obtained as views of the 'measured edge' taken with the support edge 'edge' using appropriate microscopic measuring devices of sufficient quality and magnification. The data presented here was obtained using the following equipment: Keyence VH-6 100 video unit (20x magnification), with video image prints made using a Sony Video printer and a Mavigraph unit. Video prints were scanned using a Hewlett Packard ScanJet ΠΡ scanner. Image analysis was performed on a Macintosh IlCi computer using NIH MAC Image software, version 1.45.

Using the present invention, it is first necessary to take a snapshot image of a calibration grid having a scale of about 12.7 mm with marks of about 0.127 mm that is used to calibrate the computer image analysis program. All samples to be measured are then video-captured and printed. In addition, all prints of video images are scanned at 100 dpi (256-level grayscale) into a suitable Mac image file format. Finally, each image file (including the calibration file) is analyzed using Mac Image 1.45. All samples are measured with the selected manual length gauge. The samples are measured at both side edges and the respective lengths are recorded as simple as film thin (thin and constant thickness) samples require only one end edge to be measured. Samples of laminate and thick foam are measured at both side edges. The length measurement must be monitored along the entire measured length of the cut sample. In cases of highly distorted samples, more (partially overlapping) images may be required to cover the entire cut sample to cover the entire cut sample. In these cases, the features common to the two overlapping images are selected and used as "marks" to allow the reading of adjacent image lengths but not overlapping.

The final determination of the surface path lengths for each region is obtained by averaging the lengths of five (5) separate measured approximately 1.27 mm samples from each region. The "surface path length" of each measured sample shall be the average of the surface path lengths of the two lateral edges.

Poisson lateral contraction

Poisson lateral contraction is measured on an Instron Model 1 122 as available from Instron Corporation of Canton, Massachusetts, USA, which is connected to a Gateway 2000 486/33 Hz computer from Gateway 2000 z N. Sioux City, South Dakota, USA using the TestWorks ™ software, available from Sintech, Inc. from Research Triangle Park, North Carolina, USA. All essential parameters required for testing are included in the TestWorks ™ software for each test. Data collection is performed through a combination of manual sample width measurements and elongation measurements performed with TestWorks ™.

The samples used for this test are 2.54 cm wide and 10.15 cm long, with the long axis of the cut sample parallel to the direction of the first region of the sample. The specimen should be cut with a sharp knife or a suitably sharp cutting device designed to cut specimens of an exact width of 2.54 cm. It is important that the “representative sample” is cut to represent the area representing the symmetry of the total sample of the deformed region. There will be cases (due to variations in either the size of the deformed portion or the relative geometries of the first and second regions) where it will be necessary to cut either larger or smaller samples than recommended here. In this case, it is very important to note (together with all the reported data) the size of the sample, from which region of the deformed region it was taken, and preferably to attach a diagram of the representative region used for

-24GB 292297 B6 sample. Generally, the "aspect ratio" (2: 1) for the tensile elongated portion (length to width 1) should generally be maintained if possible. Five samples are tested.

The Instron jaws consist of air-operated jaws designed to concentrate all clamping force along a single line perpendicular to the direction in which the elongation is tested, and have one flat surface and the opposite side from which the semicircle protrudes. No slip should be allowed between the specimen and the jaws. The distance between the clamping force lines should be 5.08 cm, measured by a steel ruler held next to these jaws. This distance will be referred to hereinafter as the "measured length".

The sample is fixed in the jaws with its long axis perpendicular to the direction of the applied elongation. The area representing the overall geometry of the pattern needs to be symmetrically centered between the jaws. The crosshead speed is set to 25.4cm / min. The crosshead moves to the prescribed elongation (measurements are taken at both 20% and 60% elongation). The width of the sample at its narrowest point (w2 ~) is measured to the nearest 0.508 mm using a steel ruler. The extension in the direction of the applied elongation is recorded at the nearest 0.508 mm in the TestWorks software. The Poisson lateral contraction effect (Poissn's Lateral Contraction Effect, abbreviated to PLCE) is calculated using the following formula:

K- ^W _t l

W1

PLCE = ---------------- H _and -hl where: w ₂ = width of specimen at longitudinal extension applied, wi = original width of specimen,

1 ₂ = length of the sample when the elongation is applied, and li = original length of the sample (measured length).

Measurements are performed at both 20% and 60% elongation, using five different samples for each given elongation. The PLCE at a given percentage elongation is the average of five measurements.

Hysteresis test

The hysteresis test is used to measure the permanent deformation in percent and the relative decrease in force in percent of a material. Tests are performed on an Instron Model 1122 as available from Instron Corporation of Canton, Massachusetts, USA, which is connected to a Gateway 2000 486/33 Hz computer from Gateway 2000 of N. Sioux City, NC South Dakota 57,049, in the US using TestWorks ™ software from Sintech, Inc. from Research Triangle Park, North Carolina 27,709, USA. All essential parameters required for testing are embedded in the TestWorks ™ software (ie, crosshead speed, maximum percentage elongation point, and residence time) for each test. All data collection, analysis and graphing is also performed using TestWorks ™ software.

The samples used for this test are 2.54 cm wide and 10.15 cm long, with the long axis of the cut sample parallel to the direction of maximum extensibility of the sample. The sample should be cut with a sharp cut

Exacto with a knife or some suitably sharp cutting device designed to cut a specimen of an exact width of 2.54 cm (if there is more than one direction of stretching of the material, the specimens should be taken parallel to each direction of stretching). The sample should be cut so that the area representing the symmetry of the overall pattern of the deformed region is represented. There will be cases (due to variations in either the size of the deformed portion or the relative geometries of the first and second regions) where it will be necessary to cut either larger or smaller samples than recommended here. In this case, it is very important to note (together with all data communicated) the size of the sample from which area of the deformed region it was taken, and preferably to include a diagram of the representative area used for the sample. For each material, three separate tests are typically measured at 20.60 and 100% elongation. Three samples of the material are tested for each percent elongation.

The Instron jaws consist of air operated jaws designed to concentrate all clamping force along a single line perpendicular to the direction of the test load, with one flat surface and an opposing surface from which a semicircle protrudes to minimize sample slippage. The distance between the clamping force lines should be 5.08 cm, measured by a steel ruler held next to the jaws. This distance will be referred to hereinafter as the "measured length". The sample is fixed in the jaws with its long axis perpendicular to the direction of the applied elongation in percentage. The crosshead speed is set to 25.4cm / min. The crusader moves to the prescribed maximum percent elongation and holds the specimen at that percent elongation for 30 seconds. After 30 seconds, the crusher returns to its original position (0% elongation) and remains in that position for 60 seconds. the crusader returns to the same maximum percentage of elongation as used in the first cycle, stays there for thirty seconds, and then returns to zero.

A graph is created for two cycles. An example of such a graph is shown in Fig. 7. The relative decrease in force in percent after a 30 s delay is determined by the following calculation from the data for the force from the first cycle:

relative force at max.% elongation - this force after 30 s delay force decrease% = ------------------------------- ---------------------------- x 100 force at max.% elongation (1st cycle)

Permanent percent deformation is the relative elongation in percent of the sample in the second cycle where the sample begins to resist elongation. The permanent percent deformation and the percent force reduction are also shown graphically in Figures 7 and 15. the percent elongation gives the average relative force decrease in percent and the permanent deformation in percent for the three samples.

Tensile strength test

The tensile strength test is used to measure the force dependence on the percent elongation and the available elongation of the material. The tests are performed on an Instron Model 1 122 instrument available from Instron Corporation of Canton, Massachusetts, USA, which is connected to a Gateway 2000 486/33 Hz computer from Gateway 2000 from N. Sioux City in South Dakota 57,049, in the United States using TestWorks ™ software from Sintech, Inc. from Research Triangle Park, North Carolina 27,709, USA. All essential parameters required for testing are embedded in the TestWorks ™ software for each test. All data collection, analysis and graphing is also performed using TestWorks ™ software.

The samples used for this test are 2.54 cm wide and 10.15 cm long, with the axis of the cut sample parallel to the direction of maximum extensibility of the sample. The sample should be cut with a sharp exacto knife or some suitably sharp cutting device designed to cut the sample

-26GB 292297 B6 2.54 cm wide width. (If there is more than one direction of extensibility of a material, the specimens should be taken in parallel to each of them. The specimen should be cut to represent the area representing the symmetry of the overall pattern of the deformed region. parts or relative geometries of the first and second regions) in which it will be necessary to cut either larger or smaller samples than recommended here, in which case it is very important to note (together with all data reported) the size of the sample, A sample of the representative area used for the sample was taken and preferably attached, with three samples being tested for the material.

The Instron jaws consist of air-operated jaws designed to concentrate all clamping force along a single line perpendicular to the direction of the test stress, and have one flat surface and an opposed semicircular protruding face to minimize sample slippage. The distance between the clamping force lines should be 5.08 cm, measured by a steel ruler held next to the jaws. This distance will be referred to hereinafter as the "measured length". The sample is fixed in the jaws with its long axis perpendicular to the direction of the applied elongation in percentage. The crosshead speed is set to 25.4 cm / min. The crusher extends the sample until it breaks, at which point the crusher stops and returns to its starting position (0% elongation).

The percentage of available elongation is the point at which inflection occurs on the force-elongation curve, and beyond this point, the magnitude of the force needed to further elongate the sample increases rapidly. The diameter of the applicable elongation as a percentage for the three samples is recorded.

Although the above-described testing methods are applicable to many web materials of the present invention, it is understood that the testing methods may need to be adapted to accommodate some of the more complex web materials of a structural as resilient film that fall within the scope of the present invention.

While particular embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. Accordingly, the appended claims seek to cover such changes and modifications that are within the scope of the present invention.

Claims (4)

PATENT CLAIMS A unitary disposable absorbent article comprising a chassis assembly (22) having lateral edges (60) and foot edges (61), the chassis assembly (22) comprising a topsheet (24) and a backsheet (26) and an absorbent core (28) positioned internally between the topsheet (24) and the backsheet (26), the absorbent core (28) having side edges (58) and belt edges (59), an extensible waistband (32) attached to the chassis assembly (22) adjacent one of a lateral edge (60); and a fastening system (34) associated with an extensible waistband (32) securing the absorbent article to the wearer, the absorbent article having an absorbent article surface, wherein the extensible waistband (32) has a central waistband (56). and a side panel (57) disposed on each side of the central waist panel (56), each side panel (57) extending laterally outward beyond one of the leg edges (61), the extensible waistband 32) comprising a web of seemingly resilient film (52), the web of seemingly resilient film (52) comprising an extendable network having a first region (64) and a second region (66) formed with substantially the same material composition, the first region (64) exhibits a first apparent resistive force at axial elastic extension, and a second region (66) exhibits a second different resistive force at further axial extension, generating at least two degrees of resistive force in use, and wherein the disposable absorbent article is sized for infants with a gauge dimension, given by a navel-to-cross dimension of less than 443 mm; and an absorbency index of the absorbent article defined as the ratio of the area of the absorbent article to the characteristic gauge dimension, is less than or equal to 240. A unitary disposable absorbent article according to claim 1, wherein the absorbent core (28) has an absorbent core area (28) and wherein the absorbent article has an absorbency index given by the ratio of the area of the absorbent core (28) to a characteristic dimension for growth less than and or equal to 95. A unitary disposable absorbent article according to claim 1 or 2, wherein the web of structurally resilient film (52) comprises a laminate of at least two layers. A unitary disposable absorbent article according to claims 1 to 3, wherein the absorbent article has an fit index less than or equal to 236 and an absorbency index less than or equal to 85.